Trivalent chromium (Cr(III)) from the tanning industry presents considerable environmental hazards due to its bio accumulative toxicity. This work investigates a sustainable waste management approach by incorporating Cr(III)-contaminated activated carbon (AC) into cementitious materials. The primary aim was to assess the mechanical properties of cement mortars, including different concentrations of contaminated AC—specifically, 1%, 5%, and 8% by weight of cement. The findings revealed that the incorporation of AC enhanced the mechanical properties of mortar mixtures. Compressive strength increased by up to 20%, while flexural strength improved by roughly 15% relative to normal mortar. At 28 days, the compressive strength of the MP1% mixture attained 53.3 MPa, in contrast to 19.2 MPa at 2 days, indicating there can be significant long-term strength progression. When combining 5% MP with 28 days curing conditions, the pressure was 46.8 MPa. As demonstrated by Scanning Electron Microscopy (SEM), the AC had reacted with the cement matrix and yielded a denser microstructure with fewer voids. FTIR and XRD analysis confirmed the formation of new chemical bonds related to AC’s pozzolanic activity that improved the mechanical properties. In this paper, a new method is reported for incorporating Cr-containing activated carbon into cementitious material, offering an eco-friendly method for treating hazardous waste, and is in good accordance with a sustainable economy in transit.
